BACKGROUND: A few of fibers have been used to reinforce the strength and fracture resistance of calcium phosphate cement. OBJECTIVE: To investigate the influence of gelatin combined with chitosan fiber on the mechanical properties of calcium phosphate cement and to look for a more appropriate ratio. METHODS: Comparisons and to look of chitosan fibers at volume fractions of 0, 10%, 30% and 50% together with distilled water or gelatin at mass fraction of 5% respectively in their effects on flexural strength of cement were performed. 2 ×4 factorial design was adopted. Flexural strength of cement composite fractures was detected, and fractured surface morphology was observed by scanning electron microscope. Energy dispersion analysis was also performed on particles of composites. RESULTS AND CONCLUSION: A significant difference was found between the flexural strength of different gelatin groups and between the flexural strength of different volume fraction groups (P < 0. 001). The maximal flexural strength was obtained when the calcium phosphate cement was reinforced with fiber at volume fraction of 30% and gelatin at mass fraction of 5%, which was 12. 31 MPa. With distilled water as the liquid phase, there were irregular particles (mean pore diameter < 5 μm) on the surface of the solidified calcium phosphate cement. After gelatin adding, gelatin and particles seemed to stick together, and the mean pore diameter was similar to the above-mentioned, but the number was less than the former. A great amount of particles were seen at the fractured surface of calcium phosphate cement reinforced with fiber at volume fraction of 30% and gelatin at mass fraction of 5%, and the number of particles was decreased significantly at the fractured surface of calcium phosphate cement reinforced with distilled water and fiber at volume fraction of 30%. The mechanical property of calcium phosphate cement could be enhanced by using gelatin and chitosan fiber as two reinforcement agents, and gelatin at the mass fraction of 5% and chitosan fiber at the volume fraction of 30% might be a better ratio for this reinforcement mode.
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